用OpenGL在 visual studio 2005 下画简单的二维函数图像

书上又一例子，画公式 f(x) = e-x cos(2*pi*x) 的曲线，效果如下：



这是我在visual studio 2005 下编译通过的源代码：


// Draw the "dot plots" of a function


//P52 in <Computer Graphics Using OpenGL(Second Edition)>




#include<math.h>


#include<GL/glut.h>




const int screenWidth = 640; // width of screen window in pixels


const int screenHeight = 480; // height of screen window in pixels


GLdouble A,B,C,D; // values used for scaling and shifting




//----------Initialization--------------


void init(void)




...{


glClearColor(1.0,1.0,1.0,0.0); // Set white background color


glColor3f(0.0f,0.0f,0.0f); // Drawing color is black


glPointSize(2.0); // a 'dot' is 2 by 2 pixels


glMatrixMode(GL_PROJECTION); // Set "camera shape"


glLoadIdentity();


gluOrtho2D(0.0,(GLdouble)screenWidth,0.0,(GLdouble)screenHeight);


// Set values used for scaling and shifting


A = screenWidth/4.0;


B = 0.0;


C = D = screenHeight/2.0;




}




// --------Draw the "dot plots" of a function------


void dotPlots(void)




...{


glClear(GL_COLOR_BUFFER_BIT); //clear the screen


glBegin(GL_POINTS);


for(GLdouble x = 0;x<4.0;x += 0.005)




...{


GLdouble func = exp(-x) * cos(2*3.14159265*x);


glVertex2d(A*x+B,C*func+D);


}


glEnd();


// Draw a horizontal line


glBegin(GL_LINES);


glVertex2i(0,screenHeight/2);


glVertex2i(screenWidth,screenHeight/2);


glEnd();


glFlush(); //send all output to display


}




//--------main-----------


void main(int argc,char** argv)




...{


glutInit(&argc, argv); // Initialize the toolkit


glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE); // Set display mode


glutInitWindowPosition(100, 150); // Set window pozition on screen


glutInitWindowSize(screenWidth, screenHeight); // Set window size


glutCreateWindow("Dot plot of a Function"); // Open the screen window


glutDisplayFunc(dotPlots); // Register redraw function


init();


glutMainLoop(); // Go into a perpetual loop


}

在上面的 dotPlot（）中的for循环里做一些更改就可以画另一个函数图了